Feat: 스터디룸 채팅 Repository QueryDSL 적용

- RoomChatMessageRepositoryCustom 인터페이스 구현
- QueryDSL로 동적 쿼리 및 Fetch Join 적용
- before 파라미터 완전 지원 (기존 TODO 해결)

Author: jueunk617

src/main/java/com/back/domain/chat/service/ChatService.java

@@ -59,10 +59,9 @@ public ChatPageResponse getRoomChatHistory(Long roomId, int page, int size, Loca
         // before 파라미터가 있으면 해당 시점 이전 메시지만 조회
         Page<RoomChatMessage> messagesPage;
         if (before != null) {
-            // TODO: before 조건 추가한 Repository 메서드 필요
-            messagesPage = roomChatMessageRepository.findByRoomIdOrderByCreatedAtDesc(roomId, pageable);
+            messagesPage = roomChatMessageRepository.findMessagesByRoomIdBefore(roomId, before, pageable);
         } else {
-            messagesPage = roomChatMessageRepository.findByRoomIdOrderByCreatedAtDesc(roomId, pageable);
+            messagesPage = roomChatMessageRepository.findMessagesByRoomId(roomId, pageable);
         }
 
         Page<ChatMessageDto> dtoPage = messagesPage.map(this::convertToDto);

src/main/java/com/back/domain/studyroom/repository/RoomChatMessageRepository.java

@@ -1,36 +1,9 @@
 package com.back.domain.studyroom.repository;
 
 import com.back.domain.studyroom.entity.RoomChatMessage;
-import org.springframework.data.domain.Page;
-import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
-import org.springframework.data.jpa.repository.Query;
-import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 
-import java.time.LocalDateTime;
-import java.util.List;
-
 @Repository
-public interface RoomChatMessageRepository extends JpaRepository<RoomChatMessage, Long> {
-
-    // 방별 페이징된 채팅 메시지 조회 (무한 스크롤용)
-    @Query("SELECT m FROM RoomChatMessage m " +
-            "WHERE m.room.id = :roomId " +
-            "ORDER BY m.createdAt DESC")
-    Page<RoomChatMessage> findByRoomIdOrderByCreatedAtDesc(@Param("roomId") Long roomId, Pageable pageable);
-
-    // 특정 타임스탬프 이후의 메시지 조회 (실시간 업데이트용)
-    @Query("SELECT m FROM RoomChatMessage m " +
-            "WHERE m.room.id = :roomId " +
-            "AND m.createdAt > :timestamp " +
-            "ORDER BY m.createdAt ASC")
-    List<RoomChatMessage> findByRoomIdAfterTimestamp(@Param("roomId") Long roomId,
-                                                     @Param("timestamp") LocalDateTime timestamp);
-
-    // 방별 최근 20개 메시지 조회
-    List<RoomChatMessage> findTop20ByRoomIdOrderByCreatedAtDesc(Long roomId);
-
-    // 방별 전체 메시지 수 조회
-    long countByRoomId(Long roomId);
-}
+public interface RoomChatMessageRepository extends JpaRepository<RoomChatMessage, Long>, RoomChatMessageRepositoryCustom {
+}

src/main/java/com/back/domain/studyroom/repository/RoomChatMessageRepositoryCustom.java

@@ -0,0 +1,28 @@
+package com.back.domain.studyroom.repository;
+
+import com.back.domain.studyroom.entity.RoomChatMessage;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+
+import java.time.LocalDateTime;
+
+public interface RoomChatMessageRepositoryCustom {
+
+    /**
+     * 방별 페이징된 채팅 메시지 조회 (최신순)
+     * @param roomId 방 ID
+     * @param pageable 페이징 정보
+     * @return 페이징된 채팅 메시지 목록
+     */
+    Page<RoomChatMessage> findMessagesByRoomId(Long roomId, Pageable pageable);
+
+    /**
+     * 특정 시점 이전의 채팅 메시지 조회 (무한 스크롤용)
+     * @param roomId 방 ID
+     * @param before 기준 시점
+     * @param pageable 페이징 정보
+     * @return 기준 시점 이전의 메시지 목록
+     */
+    Page<RoomChatMessage> findMessagesByRoomIdBefore(Long roomId, LocalDateTime before, Pageable pageable);
+
+}

src/main/java/com/back/domain/studyroom/repository/RoomChatMessageRepositoryImpl.java

@@ -0,0 +1,83 @@
+package com.back.domain.studyroom.repository;
+
+import com.back.domain.studyroom.entity.QRoom;
+import com.back.domain.studyroom.entity.QRoomChatMessage;
+import com.back.domain.studyroom.entity.RoomChatMessage;
+import com.back.domain.user.entity.QUser;
+import com.querydsl.core.types.dsl.BooleanExpression;
+import com.querydsl.jpa.impl.JPAQueryFactory;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageImpl;
+import org.springframework.data.domain.Pageable;
+import org.springframework.stereotype.Repository;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+
+
+@Repository
+@RequiredArgsConstructor
+public class RoomChatMessageRepositoryImpl implements RoomChatMessageRepositoryCustom {
+
+    private final JPAQueryFactory queryFactory;
+
+    private final QRoomChatMessage message = QRoomChatMessage.roomChatMessage;
+    private final QRoom room = QRoom.room;
+    private final QUser user = QUser.user;
+
+    @Override
+    public Page<RoomChatMessage> findMessagesByRoomId(Long roomId, Pageable pageable) {
+
+        // 메시지 목록 조회
+        List<RoomChatMessage> messages = queryFactory
+                .selectFrom(message)
+                .leftJoin(message.room, room).fetchJoin()  // Room 정보 즉시 로딩
+                .leftJoin(message.user, user).fetchJoin()  // User 정보 즉시 로딩
+                .where(message.room.id.eq(roomId))
+                .orderBy(message.createdAt.desc()) // 최신순 정렬
+                .offset(pageable.getOffset())
+                .limit(pageable.getPageSize())
+                .fetch();
+
+        // 전체 개수 조회
+        Long totalCount = queryFactory
+                .select(message.count())
+                .from(message)
+                .where(message.room.id.eq(roomId))
+                .fetchOne();
+
+        return new PageImpl<>(messages, pageable, totalCount != null ? totalCount : 0);
+    }
+
+    @Override
+    public Page<RoomChatMessage> findMessagesByRoomIdBefore(Long roomId, LocalDateTime before, Pageable pageable) {
+
+        // 조건부 WHERE 절 (before가 null이면 조건 제외)
+        BooleanExpression whereClause = message.room.id.eq(roomId);
+        if (before != null) {
+            whereClause = whereClause.and(message.createdAt.lt(before)); // before 시점 이전
+        }
+
+        List<RoomChatMessage> messages = queryFactory
+                .selectFrom(message)
+                .leftJoin(message.room, room).fetchJoin()
+                .leftJoin(message.user, user).fetchJoin()
+                .where(whereClause)
+                .orderBy(message.createdAt.desc())
+                .offset(pageable.getOffset())
+                .limit(pageable.getPageSize())
+                .fetch();
+
+        // 조건에 맞는 전체 개수
+        Long totalCount = queryFactory
+                .select(message.count())
+                .from(message)
+                .where(whereClause)
+                .fetchOne();
+
+        return new PageImpl<>(messages, pageable, totalCount != null ? totalCount : 0);
+    }
+
+}

src/main/java/com/back/global/config/QueryDslConfig.java

@@ -0,0 +1,25 @@
+package com.back.global.config;
+
+import com.querydsl.jpa.impl.JPAQueryFactory;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.PersistenceContext;
+import lombok.RequiredArgsConstructor;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * QueryDSL 설정
+ * JPAQueryFactory 빈을 생성하여 QueryDSL 사용 가능하게 함
+ */
+@Configuration
+@RequiredArgsConstructor
+public class QueryDslConfig {
+
+    @PersistenceContext
+    private final EntityManager entityManager;
+
+    @Bean
+    public JPAQueryFactory jpaQueryFactory() {
+        return new JPAQueryFactory(entityManager);
+    }
+}

src/main/java/com/back/global/websocket/config/WebSocketConfig.java renamed to src/main/java/com/back/global/config/WebSocketConfig.java

@@ -1,4 +1,4 @@
-package com.back.global.websocket.config;
+package com.back.global.config;
 
 import com.back.global.security.CustomUserDetails;
 import com.back.global.security.JwtTokenProvider;